600 BC -Early magnetism

Thales of Miletos (624 BC -546 BC)

Thales of Miletos was greek philosopher, mathematician and natural scientist in the 6th century BC. He observed that loadstones attracted iron.

A loadstone is a naturally occurring magnet. It is a form of iron ore that keeps it’s magnetic properties, perhaps after being struck by lighting. If iron is struck by lighting it will become magnetic for a short time. We can simulate Thales observations.

Experiment – what is attracted to a magnet:

 

Take a small pieces of steal (not stainless) or iron and see how they react to a magnet. See what else you can find that is attracted to a magnet? How about other other kind of metal like coper and aluminum.

 

Experiment – Attraction magnets:

What happens, if you take 2 magnets and try touch in the ends. What if you try the other end of one of the magnets?

 

How do magnets work?

A magnet is a object that has a lot of it’s atoms electrons spin orientated in the same direction. The more electrons spinning in the same direction the more powerful the magnet. This creates a magnetic field. The magnetic field is goes in one direction and opposite ends of the of the magnet attract each other. These ends are referred to a poles. The opposite poles are attracted to each other because the spin of the electrons are going in the same direction and so it the magnetic field. So, when you place two magnets to gather you get one magnetic field.

Experiment – seeing magnetic fields I:

You can see they magnetic field, by placing a piece of paper over a magnet and shaking iron filing over the paper. The filings will line up with the magnetic fields.

Experiment – seeing magnetic fields II:

Now, take 2 magnets and put them about 1/3 of the way from the end of the sheet of pager and sprinkle filing over the paper. You will see the magnetic fields of each magnet. Take 2 rules and slowly move the iron magnets closer together. What happens when the magnets finally touch.

Experiment – seeing magnetic fields III:

Another way to see the magnetic fields is to place put the filing into a clear bottle of baby oil. Then shake the bottle and place the magnet on the bottle. The filings will align themselves in 3 dimensions, showing that the magnetic fields are all around the magnet.

 

Why is some metal attracted to the magnet?

Some metal are attracted to magnets, because in a magnetic field they become magnets themselves. Some of the atoms in metal change their alignment so that the spin of the electrons align with the magnetic fields of the magnet. Thus, they become a magnet themselves and are attracted to the magnet. Just like when you placed the opposite poles of the magnets close to each other. Once the metal is out of the magnetic fields the atoms quickly loose there alignment and their magnetic properties.

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